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Definitions Two kinds of formal definitions are found in the literature on systems thinking and systems ‘science’, (i) Top-down (objectivist) definition: Systems are complexes of elements and relations, separated by boundaries from their environment, which is always more complex than the system itself. (ii) Bottom-up (subjectivist) definition: An assembly of parts connected in an organised way that has been identified by someone as a special interest and that behaves in some way (i.e. does more than just exist).

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Parts, Properties & Behaviour (1) By either definition, the elements that make up the system have the following three properties: 1.The properties or behaviour of each element in the system has an effect on the properties or behaviour of the system as a whole. For example, every organ in an animal’s body affects the performance of the body. 2.The properties and behaviour of each part and the way it affects the whole depends on at least one other element. Therefore, no part has an independent effect on the whole and each is affected by at least one other part. For example, the effect the heart has on the body depends on the behaviour of the lungs.

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Parts, Properties & Behaviour (2) 3. Every possible subgroup of elements in the system has the first two properties; that is, each has an effect, and none has an independent effect, on the whole. Therefore, the elements cannot be organised into independent subgroups. A system cannot be divided into independent subsystems. For example, all the subsystems in an animal’s body, such as the nervous, respiratory, digestive, skeletal & motor subsystems interact and each affects the performance of the whole.

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Open and Closed Systems Systems theory makes the distinction between ‘ open ’ and ‘ closed ’ systems. A closed system is self contained and has no inputs from or outputs to its environment. A closed system

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A closed system is a “ theoretical ” concept often used in scientific theorising and experimentation. In fact, you can think of a scientific experiment as an act of constructing and using a closed system. That is, by first identifying a set of variables, then by isolating those variables (excluding the rest of the world) and then by observing the emergent interactions and deducing some regularity of behaviour or outcome. Can closed systems really exist? What might be a logical argument against such systems existing in the real world? Closed Systems

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An open system has inputs from and outputs to its environment. That is, it exchanges material, information or energy with its environment across its boundary. Open Systems An open system

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All biological and social systems are open systems in that they are in a dynamic relationship with their environments and receive various inputs, transform these inputs in some way, and export various outputs (some even unplanned for or unintended). It is often helpful to conceptualise open systems as simultaneously existing in both a network relationship with other systems and also as being embedded in one or more higher order systems. Open Systems (cont.)

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A system containing other systems and interacting with its environment

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Reductionism & Holism The classical scientific approach relied on the powerful technique known as ‘ reductionism ’ which seeks to break things down into their constituent parts and analyse these parts independently of the whole. This worked very well in the early days of the natural sciences, but it came to be noticed that reductionist analysis misses the behaviour or outcomes – referred to as “ emergent properties ” or “ emergence ” – that occurs as a result of the elements & subsystems interacting and is only explainable at the level of the whole system. The idea that the “ whole is more than the sum of its parts ”. Hence the idea of holistic (expansionist) analysis or holism - to study the system and its outcomes at the level of the system itself. Systems theory does not reject reductionism but supplements the reductionist ‘ bottom-up ’ approach with a holistic ‘ top- down ’ approach.

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Hierarchy & Levels of resolution Open systems always exist within networks of other systems and a special case of the network is the hierarchy. It is easy to see that the environment, system, subsystems & elements are hierarchically organised with one ‘ containing ’ the other. At the level of the environment, the system appears very coarse grained as it is just one system among others; at the level of the system, the resolution reveals the subsystems and their relationships, at the level of a particular subsystem, the individual elements and their connections can be observed. This idea of going between levels to resolve the different strata of the systems hierarchy is known as ‘ functional decomposition ’ and is a commonly used technique within systems analysis.

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Feedback, feedforward & homeostasis A system will have a set of behaviours or outcomes that have to fall within the expected or reference range. This is known as the systems equilibrium or ideal state and is a measure of how well the system is meeting its goal. Maintaining the system in a relatively constant state (i.e. within the reference range) is known as homeostasis. Two important mechanisms employed to keep the system in a homeostatic state are - feedback or closed-loop – where the outputs are monitored and the inputs are adjusted to bring the system back to equilibrium if the outputs go beyond the reference range & - feedforward or open-loop – where the inputs are adjusted in anticipation of the output range going beyond the reference range.

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Systems & information systems Information systems are ‘ human activity systems ’ that are embedded within organisations and wider society. The systems approach offers a very powerful set of tools and techniques using which we can analyse, design, build and implement information systems that operate within organisations and increasingly in the internet age, between, among & for organisations. Systems theory allows us to model both the ‘ organisational ’ or ‘ soft ’ aspects of the application domain as well the technical or ‘ hard ’ aspects. In fact, it is the only mature theory that can hope to bridge the gap between the organisational (human and informal) and the informational (technical and formal) in the social space we call everyday life.

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Systems Thinking “Systems thinking is a holistic approach to analysis that focuses on the way that a system's constituent parts interrelate and how systems work over time and within the context of larger systems. The systems thinking approach contrasts with traditional analysis, which studies systems by breaking them down into their separate elements. Systems thinking can be used in any area of research and has been applied to the study of medical, environmental, political, economic, human resources, and educational systems, among many others.”